The invention relates to an electron beam apparatus provided with an electron collecting element for collecting electrons extracted from an electron emanating element and with means for generating a magnetic field in front of at least one of said elements.
Electron beam apparatus of this kind may be provided with an object to be examined such as a specimen or a chip. Such an object may be irradiated with electrons generated by an electron source and electrons emanating from the object are, preferably energy dependent, detected. Secondary electron-, reflected electron- or especially Auger electron detecting instruments as well as chip inspecting instruments belong to this kind of apparatus. In other apparatus a target such as a semi-conductor wafer becomes irradiated with electrons in order to register integrated circuit patterns therein. Electron beam pattern generators and electron beam image projectors are examples of this kind of apparatus. In image projectors electrons are extracted from a structured device such as a master chip. For chip production with an electron beam liberated from the master chip a semi-conductor wafer is irradiated in order to image the pattern of the master chip thereupon. The electrons may be liberated from the master chip with the help of a photo emitter provided on the structure thereof. In an electron beam pattern apparatus an electron beam extracted from an electron emitting cathode tip is used for producing a chip or a chip master, the latter for subsequent use in an image projector for example.
All these apparatus suffer from axial and non-axial aberrations enlarging the measuring of the electron probe and deteriorating the exactness of secondary electron detection.